84 research outputs found

    Simulation of long-term influence from technical systems on permafrost with various short-scale and hourly operation modes in Arctic region

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    Technogenic and climatic influences have a significant impact on the degradation of permafrost. Long-term forecasts of such changes during long-time periods have to be taken into account in the oil and gas and construction industries in view to development the Arctic and Subarctic regions. There are considered constantly operating technical systems (for example, oil and gas wells) that affect changes in permafrost, as well as the technical systems that have a short-term impact on permafrost (for example, flare systems for emergency flaring of associated gas). The second type of technical systems is rather complex for simulation, since it is required to reserve both short and long-scales in computations with variable time steps describing the complex technological processes. The main attention is paid to the simulation of long-term influence on the permafrost from the second type of the technical systems. © 2017 Author(s).The work was supported by Russian Foundation for Basic Research 16–01–00401 and program of scientific research UrB RAS 15–16–1–10

    Simulation of permafrost changes due to technogenic influences of different ingeneering constructions used in nothern oil and gas fields

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    Significant amount of oil and gas is producted in Russian Federation on the territories with permafrost soils. Ice-saturated rocks thawing due to global warming or effects of various human activity will be accompanied by termocarst and others dangerous geological processes in permafrost. Design and construction of well pads in permafrost zones have some special features. The main objective is to minimize the influence of different heat sources (engineering objects) inserted into permafrost and accounting long-term forecast of development of permafrost degradation due to different factors in particular generated by human activity. In this work on the basis a mathematical model and numerical algorithms approved on 11 northern oil and gas fields some effects obtained by carrying out numerical simulations for various engineering systems are discussed. © Published under licence by IOP Publishing Ltd.This work was supported by RFBR projects (16-01-00401, 14-01-00155) by contract 02.A03.21.0006 (reg.N211 of RF Government) and Program of UB RAS, project 15-7-1-13

    Использование облачных технологий при проектировании и эксплуатации нефтегазовых и геотермальных месторождений

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    Добыча нефти и газа на северных нефтегазовых месторождениях, расположенных в зоне распространения многолетнемерзлых пород (ММП), имеет свою специфику и оказывает существенное влияние на деградацию ММП из-за выделения тепла от горячей нефти, нагревающей трубы в скважинах, что в свою очередь может приводить к авариям и даже к разрушению скважин. Моделирование таких процессов с учетом фазовых превращений приводит к рассмотрению задач тепломассопереноса в сложных трехмерных средах. Если не учитывать фазовый переход, то могут, в частности, возникнут задачи, связанные с оптимальным проектированием геотермальных месторождений. Обе эти задачи требуют больших вычислительных мощностей и затрат машинного времени на проведение численного моделирования по долгосрочному прогнозированию распространения тепловых полей в неоднородном грунте со сложной литологией. В предложенной работе рассматриваются результаты, направленные на разработку методик, ориентированных на облачные технологии и многопроцессорные ЭВМ, для расчета тепловых полей как в вечной мерзлоте, от различных технических систем, влияющих друг на друга, так и при проектировании оптимальных геотермальных циклических систем.Design and operation of oil, gas, and geothermal fields generates a number of problems that require massive computations, related with series of numerical simulations in a complex three-dimensional region of heat and mass transfer processes. Mathematical formulation of some of these problems for northern oil and gas fields are presented in [1-3] for the problems associated with using geothermal heat sources are in [4]. In the presented paper the results are considered which deal with the methods focused on cloud computing and multiprocessor computations to simulations of thermal fields in permafrost around of various technical systems influenced each other, which can be a heat source (surface and underground) and a cold source (in the soil). In Russia, permafrost takes place about 60% of the total area, these areas are extremely important for economy, because produces about 93% of Russian natural gas and 75% of oil. Thawing of ice-saturated rocks due to global warming, or various technological impacts, is accompanied by subsidence of earth's surface and development of dangerous cryogenic geological processes, which called thermokarst.Over the last 10 years, only in the cities of Norilsk area about 50 high-rise buildings are demolished due to weakened of foundations. In 2007-2009, on the territory of Yamburg gas condensate field approximately 8000 pillars of pipelines are cut off because of frost heave. In permafrost about 40% of all engineering structures are subjected to a strain. According to foreign sources, annually Gazprom spends more than $1.9 billion USD to restore infrastructure affected by permafrost thawing. It was found that not only climate change, but human activities lead to permafrost degradation and it leads to big efforts to recovery the infrastructure and environment.As a rule these three-dimensional problems have to be considered in different scales of various physical and climatic factors that have to be included in the mathematical model with no popular simplification of some researchers. The paper considers a model which takes into account the following factors: emissivity, leading non-linear boundary conditions at the surface; various thermal parameters of soils constituting the permafrost, changing not only in the vertical plane; seasonal fluctuations in air temperature in the area (in summer time there is a seasonal thawing of the upper layer of soil, in winter there is freezing); possible phase transition; engineering characteristics of technical systems (various insulating materials, seasonal cooling devices used for thermal stabilization of soil), etc. The developed model, cloud environment and software package “Wellfrost” (State Registration Number 2012660988, Dec. 4, 2012) was corrected according to monitoring data for technical systems (such as production and injection wells) and permafrost by “Nordeco Eurasia” company. The computational core (software package «Wellfrost»), included in the cloud environment, from 2010 was tested in 8 oil and gas fields located in permafrost zone and is in a good (about 5%) agreement with the experimental data. The calculations showed that for solving such problems powerful multiprocessor computers are required and it is necessary to develop a user-friendly interface for cloud computing for a specific range of applications. The considered models may include problems associated with evaluation of the effects of climate change and other important problems, for example, effective extraction of geothermal heat (software package GeoTerm, State Registration Number 2014616246, Feb. 10, 2014)

    Simulation of thermal stabilization of bases under engineering structures in permafrost zone

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    Constructions on permafrost have to be ensured with reliability of the foundation, which, under the influence of various heat fluxes and annual freezing (thawing) of the soil, may get stressed, that leads to destruction of the foundation and the engineering structure itself. To assess the thermal impact of engineering structures on the ground, a computer simulation of the construction pads is used. Thermal stabilization of the soil is considered to be carried out due to freezing with the help of seasonally operating cooling devices for some time prior to the beginning of construction, or placing on site various technical systems that are sources of heat. The results of numerical calculations illustrating the effectiveness of preliminary thermal stabilization of the soil under the base of the engineering structure are presented. © 2018 Author(s).The work was supported by Russian Foundation for Basic Research 16–01–00401 and program of scientific research UrB RAS 18–1–1–8

    Thawing of Permafrost During the Operation of Wells of North-Mukerkamyl Oil and Gas Field

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    Thawing of ice-saturated rocks due to climate change or various technological impacts will be accompanied by subsidence of the earth’s surface and development of dangerous permafrost geological processes called thermokarst, leading to accidents, which may destruct the wells. Currently, the investment programs of the development of new northern oil and gas fields are restricted. In this regard, reducing the cost of developing the oil and gas fields is an urgent problem. For example, diminishing the area of well pads and maintaining efficiency in the northern oil and gas fields can significantly reduce the costs, in particular, during the design stage. A model of unsteady thermal fields propagation in frozen soil from new well construction for the North Mukerkamyl oil and gas field is developed, taking into account the construction features, the annulus, and the complex lithology of the soil surrounding the well. It is planned to take into account climatic and technological factors, in particular, an annual rest period of well operation, which held from several hours to two weeks. The paper discusses the computational features of the thermal fields calculating in frozen ground from wells and explores the influence of various parameters, which in the computations may lead to a significant increasing of thawing area in the well pads. © Siberian Federal University. All rights reserved.The work was supported by Russian Foundation for Basic Research 19–07–00435

    Simulation of thermal effects of engineering objects in the arctic regions on the permafrost boundaries

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    The paper discusses a mathematical model for describing heat distribution in the surface layer of soil from various sources of heat, or cold, which, together with seasonal climatic changes, form unsteady thermal fields in the soil. The developed algorithms are focused on high-performance computers and were used in the design of various oil and gas fields located in permafrost zone. The main attention is paid to adequate setting of boundary conditions and maximum consideration of various parameters, including technical characteristics of engineering objects, climatic conditions and soil lithology in the field of modeling thermal fields. The presented numerical calculations show the possibility of using these models and algorithms for forecasting of the development of thermal processes in the soil. Minimization of heat effect of the systems inserted into permafrost will avoid accidents, in particular, at oil and gas fields related to the changes in temperature of the soil, and increase the stability of the building with pile foundations. In the paper the possibility of the heat impact compensation in permafrost is discussed. © 2021 Author(s).The work was supported by Russian Foundation for Basic Research 19–07–00435

    Automated Monitoring the Temperature under Buildings with Pile Foundations in Salekhard

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    In the paper, we consider a method of ground temperature monitoring using the thermometric boreholes and computer modeling the residential buildings with the pile foundation in the city of Salekhard; note that it is located in the permafrost zone. Construction of the residential buildings and industrial structures in the permafrost zone and their operation is carried out according to the principle of preserving the frozen state of foundations. For ground temperature monitoring, thermometric boreholes are used. In a given time period, the measured temperatures are transferred to a server for further processing. Information about the temperature is an important factor for the safety of the buildings and it can be used to evaluate the piles bearing capacity. It allows to propose options for the soil thermal stabilization or to eliminate the detected technogenic heat sources. An approach of mathematical modeling to reconstruct the temperature fields in the pile foundation base of a building is discussed taking into account the data of temperature monitoring. 24 boreholes were equipped with more than 400 in-borehole thermal sensors for testing the method under the residential building I. The preliminary modeling is carried out for December and January 2020 for the contact thermal conductivity model with phase transition with the upper part of the geological section typical for Salekhard (the sandy soils). The modeling describes the freezing processes during the months in detail. The thermal monitoring allows to say that the ground in the base of the Residential building I is stable. But there are detected heat transfers near the borehole T1 at the depth of 12–14 m. The combination of monitoring and computer modeling makes it possible to assess the safety of the operation of the residential buildings in cities located in the permafrost zones. © 2021, Russian Geographical Society. All rights reserved

    Pechora Sea Environments : Past, Present, and the Future

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